Lever

Have you ever used a spoon to lift the lid of a jar or played on a seesaw? If so, then you’ve used a lever!

A lever is one of the simplest and most powerful machines. It makes lifting or moving things easier.

At its core, a lever is just a rigid bar that pivots around a fixed point called the fulcrum.

Every lever has three main parts: the fulcrum, which is the pivot; the effort, where you apply force; and the load, which is the object you want to move.

But what makes a lever special is how its parts are arranged. Depending on their placement, there are three classes of levers.

In the first class, the fulcrum is in the middle, as in scissors or a seesaw.

In the second class, the load is in the middle, as in a wheelbarrow.

In the third class, the effort is in the middle, as in tweezers or your arm.

Levers are everywhere—from a crowbar lifting a heavy lid to your knees bending as you walk.